1. Field of the Invention
The invention relates generally to agents and methods for preventing a viral or microbial infection and, more specifically, to compositions containing a β-cyclodextrin and methods of using such compositions to reduce the risk of transmission of a sexually transmitted disease.
2. Background Information
Sexually transmitted diseases (STDs) are among the most common types of infections. Three bacterial STDs—gonorrhea, chlamydial infections, and syphilis—are particularly common, and account for a great deal of morbidity, including infertility, ectopic pregnancy, and loss of productivity (see Harrison's “Principles of Internal Medicine” 13th edition (ed. Isselbacher et al.; McGraw-Hill, Inc. 1994), chapter 88). Among the viral STDs, human papilloma virus and hepatitis B virus are among the most common, and are associated with cervical carcinoma and hepatocellular carcinoma, respectively.
In the past couple of decades, acquired immunodeficiency disease (AIDS) associated with sexual transmission of human immunodeficiency virus (HIV) has emerged as a global health threat. In industrialized countries, education as to the use of condoms and the practice of “safe sex” reduced the levels of new HIV infection and of AIDS deaths following a peak in the mid-1990's. However, the decreased number of AIDS deaths and the availability of medications that appear to increase the life spans of AIDS patients may have created a false sense of security, and it now appears that this trend may reverse. In many non-industrialized countries, AIDS is an epidemic, and it is not inconceivable that millions may die from this disease in the next few years.
HIV can be transmitted in a number of ways, including through contaminated blood products, and from mother to offspring during gestation, child birth or breast feeding. However, newly acquired HIV infections are largely the result of sexual contact, particularly heterosexual contact. A number of factors appear to determine whether HIV is transmitted sexually, including the type of sex act, susceptibility of the exposed partner, infectivity of the infected partner, and the biological properties of the particular HIV subtype.
Prevention of the spread of HIV infection requires interventions of both the infected and uninfected populations. In particular, since only a small percentage of HIV-infected individuals are aware of their carrier status, a significant prevention effort must be made by the susceptible population. Mechanical barriers such as condoms can be effective in preventing sexual transmission of HIV. However, this method is not always accepted by male partners, and can be impractical for use by women. Topical microbicides currently available have proven inadequate, and the widely used surfactant microbicide, nonoxynol-9, which is used as a spermicide, may actually increase HIV infection by inducing genital ulcerations. Thus, in the absence of an effective vaccine, other biomedical methods must be identified, particularly those that can be practiced by the susceptible population.
Semen from HIV infected men and cervical mucus from HIV infected women contain free virus as well as HIV-infected cells and, sexual transmission of HIV may occur due to both forms of the virus. Thus, a need exists for a therapeutic agent that reduces or eliminates transmission of free HIV as well as cell-associate virus infection, thereby reducing the risk of transmission of HIV and other sexually transmitted pathogens. The present invention satisfies this need and provides additional advantages.